Fuel booster pump



July 14, 1931. c. c. BR'ADBURY FUEL BOOSTER PUMP Filed sept. 5. 1929 Vzo Patented July 14, 193i UNITED STATES PATENT OFFICE CLIFFORD C. BBADBURY, OF GLENCOE, ILLINOIS, ASSIG-N'OR TO CURTIS IB. CAMP, TRUSTEE, 0F GLF-NOCE. ILLINOIS FUEL BOOSTER PUMP Application led September 3, 1929. Serial No. 389,904.

My invention relates to vacuum apparatus and will be described with particular 'preference to a fuel lifting apparatus for motor vehicles. 4

' In climbing stee grades the fuel supply tank of a. motor ve icle which is usually located at the rear of the vehicle is much lower with respect to the engine thfan when the vehicle is `on a level road. Many types of fuel lifting devices onpthe market are not adapted to and are incapable of lifting fuel far enough to supply fuel to the auXlliary supply tank at the engine under these conditions. If the fuel supply in the auxiliary l5 or vacuum tank ofthe vehicle happens to be low at the foot of a long incline, it is apt to be exhausted beforethe top of the incline is reached, with' the result that the engine will stop for lack of fuel. s

An object of my invention is to provide anew and im roved fuel lifting apparatus.

A. further object is to provide an apparaltus for producing a high degree of vacuum lfor liftin fuel in a motor vehicle.

A furt er object is to provide a Venturi type'of vacuum device which is closed to the atmosphere preventing the passage of air therethrough until a predetermined suctionA is reached.

A further object is to provide a lvacuum device having successive cumulative stages for producing a bi h vacuum.

Other objects an advantages will appear.

as the description proceeds.

35 Referring tothe drawings;

plurality of containers 5, 6 and 7 for storingV air under low pressure, each of which has et a Venturi tube 8*, 9 and 10, respectively, as-

Fig. 3 is a section taken on the line 3--13 `sociated therewith. The yfirst Venturi tube communicated.

Each of the Venturi tubes has an internal bore provided with a tapering mouth 21 leading to a restrictedthroat 22, and rearwardly of the throat the bore is again flared outwardly as at 23. Communicating with the throat is an intake from a container comprising an aperture 24.- leading vinto a valve chamber 25. The valve chamber is adapted to receive a plug 26 threaded into the wall of the Venturi tube and into a boss 20 of the container. -The end of the plug is provided with a valve seat for receiving a ball type valve 27 which is resiliently urged to its seat by a spring 28.

Rearwardly of the flared portion 23 the tube is provided with a cylinder 31 having a plunger 32 reciprocably mountedtherein. The front face of the plunger is adaptedI to rest against a shoulder l3,3 lin the tube which may be ground to provide a closeit when the plunger is in its forward position. a pair of saw cuts 30 for admitting airto the end of the tube when the plunger is retracted. The plunger `and saw cuts thus form a valve at the end of the Venturi tube. The plunger 4is provided with a holl low bore 34 and its rearward end terminates in a radially outwardly extending flangewhich forms a piston 35 movably Y`mounted in an enlarged portion of the tube forming a cylinder 36. The plunger is provided With an annular recess andthe space sur- Immediately adjacent the shoulder is rounding the plunger and forwardly ofA cylinder 35 is connected to the atmosphere 15 cylinder 36.

by a passage 37 formedin the wall ofthe tube. v

In order to prevent the leakage of air into the cylinder 36 an annular packing ring 38 is placed at the forward end of the cylinder. Extending forwardly' Vfrom plunger 32 is a tube 41 having a slightly tapering end which extends forwardly lof the throat 22 when the plunger is in its forwardY position in which it is normally `maintained by spring 42, In the retracted position of the plunger the end of tube 41 is directly in the throat 22. This tube connects the interior of the Venturi tube with Assuming now that the motor is in operation, the manifold suction iscommunicated through tube 13 to the first Venturi tube 8. i The manifold suction is transmitted through tube 41 to cylinder 36 producing a low pressure in the cylinder. The pressure on'opposite sides of the plunger is equal at this time but the low pressure in the cylinder on the back face of piston- 35 together with atmospheric pressure through passage 37 upon the front face of piston 35, causes the piston to retract assoon as the low pressure is sufficient to. overcome the force of spring 42, drawing the plunger 32 with it. As soon -as plunger 32 iswithdrawn from shoulder 33 air will enter saw cuts and increase the pressure on the forward face of the plunger, causing the plunger to retract with a snap action. Another factor tending to cause the plunger to retract with a snap action is the fact that tube 41 in the forward position of vthe plunger extends forwardly of the throat of the Venturi tube. When the plunger retracts, the end of tube 41 will be drawn farther into the throat of the Venturi tube and thus increase the suction thereon so that as soon as the plunger begins to retract the conditions( produced thereby will move the plunger with considerable speed to its retracted position. The air drawn through the saw cuts l30 passing through the restricted throat of the. Venturi tube causes a high suction on the intake ofcontainer 5 withdrawing air from this container until the tank reaches a stage of exhaustion equal to the capacity of tube 8.

When the .suction on tube 8 by the manifold falls to a predetermined value plunger l-5 32 will again be returned to its forward positlon with a snap action. This is due to the fact that the forward movement ofy the plunger causes the end of tube 41 to'be moved forwardly of the throat of the Venturi tube and a further movement vof the plunger interrupts the passage of yair through the saw cuts thus decreasing the pressure on the face of the piston so that as soon as the pressure in the tube falls low enough to allow the plunger to begin its forward movement other factors im-A mediately tend to accelerate this movement, causing the plunger to move forward with a snap action.

The spring for maintaining the plunger of tube 9 in its forward position is made f' slightly stronger than the corresponding spring of tube 8. When container 5 reaches a given degree of exhaustion, corresponding to the strength of the spring of tube 9, suction on this tube will cause its plunger to retract and the low pressure in the container 5 `which is many times lower than that in Vthe manifold will draw air through tube 9 to produce a high suction on the intake of container 6, boosting the suction in container 6 above that of container 5. The air admitted to container 5 through tube 9 will decrease the degree of exhaustion of container 5 and allow the pressure to increase therein. As soon as the exhaustion has decreased to such an extent as to allow the plunger of tube 9 to cut off the flow of air to the container 5, vacuum will again begin to build up in container 5 untilthe suction therein is sufficient to again operate tube 9. U

Thus it will be seen'that the exhaustion of container 6 takes Aplace intermittently allowing the vacuum to build up in container 5 and then utilizing that vacuum to produce a higher vacuum in container A6. The exhaustion of container 7 takes'place in a similar manner, tube 10 having a spring of such strength as to cause the tubeto operate ona higher suction than tube 9. When the vacuum in the container 6 reaches a given value the tube 10 is operated to exhaust the air in container 7, the reduction of pressure in the container 7 taking place intermittently.

Container 7 is connectedto vacuum tank 17 in the usual manner, it being customary in some types of fuel lifting devices to connect the tubes 13 directly to the vacuum tank. By the interposition of the vacuum boosting apparatus described any desired deo gree of vacuum may be obtained to be applied to the vacuum tank.

While three stages for vincreasing -the vacuum of the manifold 'have been described, it will be understood that it is not necessary in, all cases to use three tanks and in other cases it may be desirable to use more. The invention contemplates the use of anynum- Y berof stages for `increasing the vacuum.

Having described the' naturev and embodiment of my invention, what I. desire to se cure by United States Letters Patent is as follows: l 4

1. In an apparatus y, for producing a vacuum, a Venturi tube having a restricted throat, an intake in said throat, a valve controlling the admission of air to `the end of said; tube, and means for closing said valve l'oo when the suction in the tube falls to a pre- 3u determined value and opening said valve when the suction exceeds said value to govern the withdrawal of air to produce a low pressure in means associated with said tube.

2. In an apparatus for producing a vacuum, a Venturi tube having a restricted throat, an intake in said throat, whereby a high suction is roduced at the intake by air passing throug the tube from the end of the tubefa valve at the end of the tube for controlling the admission of air thereto, means for opening said valve when the suction on the tube reaches a predetermined value, and meansfor closin 4said valve when the suction alls/'below sai value to govern the withdrawaljof'air to produce a low pressure in means associated with said tube.

3. In an apparatus for producing a vacuum, a Venturi tube having a restricted throat, an intake in said throat, a valve rearwardly of said throat for admitting air to the end of the tube, a cylinder having a movable iston therein for actuating said valve, said piston being operable in response to the degree of suction in the tube to govern the withdrawal of air to produce a low pressure in means associated with said tube.

4. In an apparatus for producing a vacuum, a Venturi tube having a restricted throat, an intake in said throat, a valve at the end of the tube having a movable plunger', said valvehaving an aperture in a position to be closed in one position of the plunger and open in another position thereof, a cylinder connected with said tube, a piston therein'for actuating the plunger ofthe valve, whereby a high suction in the tube causes the piston to actuate the'plunger to open the aperture in the valve and admit air vto the end of the tube to govern the withdrawal of air to produce a low pressure in means associated with said tube.

5. In an apparatus for producing a vacuum, a Venturi tube having a restricted throat, an intake in said throat whereby a high suction is produced at the intake byr throat of the Venturi tube when plunger' closes said passage and intothe throat when the plunger opens said passage.

6. In an apparatus for producing ajvacuum, a'Venturi tube having a .restricted throat, an intake in said throat whereby the I passage of air through the tube produces a igh suction at the intake, a passage for ad -mitting atmospheric air to the tube,a plunger for controlling said passage, means for normally retaining the plunger in a position to close said passage, a cylinder having a movable piston therein for actuating the plunger, a tube carried by the plunger for connecting the cylinder to the Venturi tube,

said tube extending forwardly of the throat of the Venturi tube when the plunger closes said passage and into the throat when the plunger opens said passage, whereby a predetermined suction in the Venturi tube causes a retraction of the plunger to open said assage.

7. n an apparatus for producing a vacuum, a Venturi tube having a restricted throat, an intake in said throat, a container connected to said intake and adapted to have air withdrawn therefrom to produce a low pressure therein, a second Venturi tube having a restricted throat and having vits mouth connected to said container, an intake in the throat of said second Venturi tube, and -means eifectin the passage of air through said secon tube only when the pressure in the container reaches a predetery mined value whereby a lower pressure is produced in .the intake of the second Venturi tube than that in the container.

8. In an apparatus for producing a vacuum, a Venturi tube having a restricted throat, la valve for admitting air to the end of said tube, an intake in said throat, means for causing the valve at the end of the tube to admit atmospheric air to theptube, means for rendering said last mentioned means ineffective when the suction in the tube falls below a predetermined value, a container connected to said intake and adapted to have air withdrawn therefrom to produce a low pressure therein, a second Venturi tube aving a `restricted throat and having its mouth connected to said container, an intake in the throat of the second Venturi tube, and means for effecting the passage of air through said second tube only when the pressure, in the container reaches a predeterf'mined value whereby a lower pressure is produced in the intake of the second Venturi tube than that in the container.

9. In an apparatus for producing a' vacuum, a plurality of` containers for storing air under low pressure, a suction device for producing a low pressure in said containers and means interconnecting said containers for transmitting low pressure from one container to a succeeding container whereby each container boosts the vacuum transmitted to the succeeding container.

10. In an apparatus for producing 'a vacuum, a container for storinv air under low pressure, a suction device or producing a low pressure in said container, a second container for storing air under low pressure, and means interconnecting said second container with the first container whereby a lower pressure will be produced in the secuugn, a Venturi tube having a restricted -throat, an intake in said throat whereby a high suction is produced at the intake by air passing throu h the tube, a valve at the end of the tube or admitting air thereto, and means associated with said valve and positioned in said throat for actuating said valve with a snap action in response to the suction within the tube.

In witness whereof, I hereunto subscribe my name this 30th day of August, 1929.

CLIFFORD C. BRADBURY. 

